mia_material for realistic leaves

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Old 05 May 2010   #61
after reading all this thread again, it's still very hard to obtain leaves like prodan's renders.
to resume things most of us are using those 2 things

1-you need a realistic tree model with sky sensitive leaves (from Onyx or Paintfx or other good software).

2-a mia_material with those settings:
diffuse weight:1
reflectibity: 1
glosiness 0.2/0.5
thin walled
fresnel reflection
ao color bleed
transparency 0.25 (compensated in the translucency color by multiply node *4)
transparency glosiness 1
translucency weight 1

again even with those values, we are still very far from realistic leaves/trees.
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Old 05 May 2010   #62
I believe your mia_material_x settings are a bit off. Why would a leaf's reflectivity be 1? And not all leaves have the same transparency; setting that to .25 seems to have no physical basis in reality. Play with the numbers to make your leaves proper. Also, a leaf wouldn't have Fresnel falloff; that's more for glass/liquids.

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Old 05 May 2010   #63
yes the reflec value is 1 but i have a reflection color map close to graythat drives the overall value so there is no 100 part reflective part on the leaf. plus u need some glosinnes.
i agree that leafs shouldnt have a fresnel falloff i am using these values here :0.001/1/1.5

now i want to make things clear for the sss textures and sss values (wich are driven by the transparency value): here is some comparisons:



full resolution
http://sor.typepad.com/files/sss_transp_values_comp.jpg

*i dont know if you guys noticed but when the directional sun (direct light) is turned off, sss effect becomes very weak on the leaves (specially the back).But in Prodan's 4th render:
http://marlas.cgsociety.org/gallery/ it seems that even with no direct ligh, the sss effect is pretty strong,
notice the branch hanging in the middle of the foreground, it's in the shade but the sss is pretty noticeable. I really wonder how this has been done.

*by sss texture i am refering to the translucensy texture.
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Last edited by royter : 05 May 2010 at 02:42 PM.
 
Old 05 May 2010   #64
Those look great, Royterr. Curious why you're not happy with your various results? I can see some of those leaves looking great in certain scenes, and some of them looking great in other scenes...

Anything else you were trying to achieve?
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Old 05 May 2010   #65
Originally Posted by InfernalDarkness: Those look great, Royterr. Curious why you're not happy with your various results? I can see some of those leaves looking great in certain scenes, and some of them looking great in other scenes...

Anything else you were trying to achieve?

the results are pretty promessing so far but not photorealistic.
i will stop when you coudnt tell if its a photo or Mr4Maya render.

now i made these tests so we could all agree on mia_material values.
we all agree on most of the values (diff bump reflec ao) regardless of the top/botoom tetxures.
it seems that the transparency value in most cases is 0.25 to 0.3 max.
the translucency must have a 4 multiplier in the direct light and more than this in the shade.
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Old 05 May 2010   #66
I think what you got is fine you just need to push it more in post. I played around with it a little in nuke and imo it looks a bit more real. Ima write more tomorrow I super tired and need sleep.
my version is on the left
 
Old 05 May 2010   #67
No offense, Royterr, but no two people will agree on photorealism generally if they know it's CG. I think your tree renders are great, but without a scene or background involved they're always gonna look CG. Quality-wise, they're perfect.

As for settings we can all agree on, that also will never happen! And most plants are VERY different. One species' settings will differ from another, sometimes vastly. Unless you plan on taking photometric measurements of light transmittal through every kind of plant available, at ever phase of their life-cycle, you're stretching too hard here. Just find settings that work for the scenes you need 'em for! I don't believe there are any universal settings, and I don't even use SSS for most of my work. I like some of yours better, but not enough to say (for example) that all plants need SSS to be "photorealistic".


Your trees look great my friend!
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Old 05 May 2010   #68
Infernal Darkness pretty much said what I was going to say. Your work is always going to look "cg" when against a flat background and no scene. You have all the surface properties in your leaves everything looks right I just think you need to create more realistic setup other then the bush agsinst a blue wall. The renders you see from prodan's work I'm pretty sure had to some extent post work: color correct,grades,chromatic abberation,bloom,etc.
 
Old 05 May 2010   #69
i perfectly agree with both of you on these points.
i know that generaly depth of field/motion blur/chromatic aberration/film grain tend to give the image that last 10 percent of reality.
But i like having a strong photorealistic base before going to post (even in front of a gray background). I usually proceed from the ground up so each element must be 99 percent photorealistic (in my eyes) before proceeding.
Anyway i am going to try to push the shader just a bit further before moving on with the rest.

*Michael i like your CA effect, did you move the rgb channels or is it a filter?
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Old 05 May 2010   #70
For the aberration I used this gizmo. I agree with you about trying to get the raw render to look as real as possible, I am this way too but what I have begun doing (on personal projects) is when my shaders are close to done I take renders into nuke and do some post work to see how they look. I my self can be very anal and picky about getting my shaders correct and as real as possible but as I began to learn more about compositing/color corrections you tend to save yourself time when it comes 3d vs 2d tweaks. I think your leaves are just as good as those renders from prodan, you have all the correct surface qualites of a leaf. But in my opinion what makes his more realistic is just the shear amount of leaves he has and and as I said before his color grades/corrects,post,etc.

Last edited by TaKIKO : 05 May 2010 at 03:46 PM.
 
Old 05 May 2010   #71
Jeff Patton recently did a nice tut on Translucency, his trick is to use the translucency lume shader.
So if maya has that you should be able to do the same.

http://jeffpatton.net/openb/index.p...s-in-mental-ray
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Old 05 May 2010   #72
Originally Posted by Spacelord: Jeff Patton recently did a nice tut on Translucency, his trick is to use the translucency lume shader.
So if maya has that you should be able to do the same.

http://jeffpatton.net/openb/index.p...s-in-mental-ray


I don't think Maya has it, but when I installed mental ray standalone 2011, I noticed the dll file in the install directory. so i guess you can use that
 
Old 06 June 2010   #73
leaf shader - gamma correct node

Originally Posted by royterr: Mrguy, you are right, i am using the gamma correct node because i am using a 2.2 gamma value in my mia_exposure_simple.So you have to correct everything, even color swatches ( i am not sure wether you have to gamma correct the "Ambient Shadow color" in the AO section)

As for the condition node, its very simple: you have a sampler info node that's inputing information about the normals and it's plugged to the first term of the condition node. and the condition node sees if the condition is availables ( so normal fliped) so if "color if true" has a white value (0 0 0) and "color if false" a 0.35 gray value.

I will post some more renders with better trees soon.


Hi there,

I was reading your post regarding gamma correction as you have 2.2 gamma value in mia_exposure_simple.

But for leaf color or translucency files cant we just increase the color gain value higher than 1. I tried both, Using the gamma correction node and the color gain value... for 2.2 gamma correct value... a value of around 1.7 color gain gave me very similar effect...

So I am wondering what I am doing is fine or am I missing something ? Kindly advise

cheers,
ak
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Old 07 July 2010   #74
Originally Posted by amitkhanna: Hi there,

I was reading your post regarding gamma correction as you have 2.2 gamma value in mia_exposure_simple.

But for leaf color or translucency files cant we just increase the color gain value higher than 1. I tried both, Using the gamma correction node and the color gain value... for 2.2 gamma correct value... a value of around 1.7 color gain gave me very similar effect...

So I am wondering what I am doing is fine or am I missing something ? Kindly advise

cheers,
ak


just use a gamma of 2.2 ans use a gamma correct node of 0.45.
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Old 08 August 2010   #75
i'm statisfied with my leaves so far, from now on it's all about finding a descent tree geometry (wich is really hard to find) to achieve a convincing organic image.I hope maya 2012 will include nice paint effects preset trees.

I am running short on time, i will pass to the grass shader now, i am satisfied with the short grass shader below, i will soon focus on medium,high grass (paint effects).

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